Heretofore, there has been known a speech recognition system that continuously recognizes speech uttered by a user, and executes a process corresponding to the recognition result (see Patent Document 1, for example). Such a speech recognition system carries out the recognition process without determining whether the user has made the speech with the intention of operating the system through speech or with the intention to talk with other users, and executes a process corresponding to the recognition result.
For example, assume that a conversation between users occurred as follows: “Which do you prefer, supermarkets or convenience stores?”, and “I would prefer convenience stores.”. Here, the users do not talk with the intention of operating the speech recognition system through speech. However, since the system continuously recognizes the speech of the users, it recognizes words, such as “supermarket” and “convenience store”, and executes process corresponding to recognition results.
In addition, if the speech recognition system fails to recognize the user's speech, it is necessary for the system to inform the user of a failure in speech recognition and the cause of the failure by output ting a speech. Thus, also in the case in which the system fails to recognize the conversation between the users above, the system outputs a speech about a failure in speech recognition.